Solvents for fat and oil antioxidants



United States Patent 6 SOLVENTS FOR FAT AND OIL ANTIOXIDANTS M B. Knowles and Herman S. Pridgen, Kingsport, Tenn., assignors to Eastman Kodak Company, Rochester, N .Y., a corporation of New Jersey No Drawing. Filed July '29, 1958, Ser. No. 751,633

11 Claims. (Cl. 99-163) This application is a continuation-in-part of copending application Ser. No. 532,123 filed September 1, 1955, which is abandoned in favor of this continuing application.

This invention relates to antioxidant compositions for fats and oils. In particular, -it relates to acetins and their utilization as solvent materials for various antioxidant compositions. These acetins can be used alone, as mixtures with themselves or as mixtures with other antioxidant solvents such as the monoand diglycerides.

Most fat and oil antioxidants are solid materials. However, commercial use often necessitates that these antioxidants be liquid. Consequently, it is necessary to employ some solvent or mixture of solvents. Such a solvent should dissolve a high concentration of the antioxidants; it should be inexpensive, odorless, colorless, tasteless, compatible with fats and oils, and preferably, it should be non-toxic.

Various solvents for fat and oil antioxidants are known and are currently in use. Perhaps the most widely used solvent is propylene glycol. This solvent is not completely satisfactory in certain cases; furthermore, a solution containing a high concentration of citric acid is impossible to achieve. Moreover, other antioxidants are only sparingly soluble in propylene glycol.

Although certain monoglycerides are good solvents for butylated hydroxytoluene, butylated hydroxyanisole, and propyl gallate, these monoglycerides are not useful in some applications requiring higher concentrations of an acid synergist, such as citric acid, because they are extremely poor solvents for citric acid. In these cases where a high concentration of acid synergist is desired, it is desirable to maintain the antioxidant concentration at as high a level as is possible and yet increase the acid synergist concentration.

Since many antioxidant compositions are mixtures of several components which usually include citric acid or other acid synergist, it is highly desirable to have a solvent which will allow the preparation of such solutions.

An object of this invention, therefore, is to provide solvents for antioxidant compositions for which there are no other satisfactory solvents at present which fulfill the desired characteristics to the requisite degree.

Another object is to provide solvents for the various acid synergists which are used in antioxidant compositions, said solvents being compatible with fats and oils and with other known solvents.

2,944,908 Patented July 12, 1960 Another object of our invention is to provide solvents for antioxidant compositions which are acceptable for food use.

A still further object of this invention is to provide an inexpensive and effective means for making solutions of the various antioxidant compositions, particularly those which comprise acid synergists.

Other objects will be apparent from the description and claims that follow.

We have found that the acetins, i.e. mono-, di-, and tri-acetin, are excellent solvents for fat and oil antioxi dants. They are particularly good solvents, when used alone or in combinations of the acetins themselves or in combinations of one or more of the acetins with other solvents, for the acid synergists as typified by citric acid, phosphoric acid, and the like. When they are used alone, or in combination with themselves or other solvents, the acetins very satisfactorily dissolve the various antioxidant compositions.

Because of the several-component composition of most antioxidant compositions, different acetins are often advantageously employed as solvents for separate materials which will make up the final solution, utilizing those acetins which are the best solvents for the respective materials. Then, since the acetins are compatible with each other, the difierent component solutions can be brought together to form the final antioxidant solution. As an example, monoacetin can be used as a solvent for an acid synergist, while triacetin can be used as a solvent for a specific antioxidant; then the two solutions can be brought together, forming a compatible antioxidant mixture in solution. In a like manner, diacetin and triacetin can be used, and other combinations of the acetins, antioxidants, acid synergists, and other solvents can be used, depending upon the type of composition which is desired as an end product. Thus, antioxidant compositions can be produced in solvent media, namely one or more of the acetins, which permits the combination of separate solutions without undergoing undesirable effects such as salt-ing out of components or separation into phases upon combination.

We have found that diacetin particularly is an excellent solvent for citric acid, and, like the other acetins, is compatible with other antioxidants and with fats and oils. Triacetin is a good solvent for all of the common fat and oil antioxidants. Mixtures of diand triacetin are very good solvents for any of the combinations of the common fat and oil antioxidants, and especially for the antioxidant compositions containing acid synergists. Monoacetin is particularly valuable as a solvent for the various acid synergists which are employed in antioxidant compositions. It has been found to be very useful when incorporated with other solvents for antioxidants, including propylene glycol and the other acetins.

One or more of the acetins can thus be used as solvents for any of the well-known antioxidants or synergists. Among the antioxidants which may be dissolved in the acetins are the phenolic antioxidants, the acetins being particularly useful as solvents for phenolic antioxidants such as butylated hydroxyanisole, butylated hydroxytoluene, propyl gallate, nordihydroguaiaretic acid, gum guaiac, the tocopherols, hydroquinone, 2,4,5-trihydroxybutyrophenone, 2,4,5 trihydroxyacetophenone, 5 acenaphthenol, etc. The acetins are also useful as solvents for other classes of fat and oil antioxidants such as glycine, lecithin, 3,3'-thiodipropionic acid and esters thereof, etc. as well as various mixtures of any of these or similar materials.

The acetins are valuable solvents for synergists such as citric acid, phosphoric acid, ascorbic acid, isopropyl citrate, and other similar materials. This is one of the most advantageous and unobvious features of this invention since a common solvent for various solutes including synergists is quite unexpected. Synergists are sometimes called metal deactivators.

The following table illustrates the solubility of typical antioxidants and synergists in the acetins when used singularly.

As is apparent from Table I, individual acetins or mixed acetins can be used without any other solvent components to dissolve various antioxidant and synergistic components. These and other stabilizers mentioned above can be readily dissolved in acetin solvents (various acetic acid esters of glycerine). The invention is particularly concerned with acetin solutions of mixtures of synergists and phenolic antioxidants (one or more of each type of component).

Any of the well-known solvents can be used in combination with the acetins and antioxidant compositions. Certain embodiments comprise using glycerine, propylene glycol, acetic acid, naturally occurring fats and oils, and products derived from naturally occurring fats and oils such as higher fatty acid monoglycerides, diglycerides, etc. in various combinations with one or more of the acetins.

The following compositions were prepared and tested. These data are given in order to illustrate the type compositions that can be made, and to indicate the Active Oxygen Method (AOM) stability provided by the particular compositions. These data are based on tests conducted under equivalent conditions employing similar samples of lard in each instance. The AOM figures are in hours required for formation of milliequivalents of peroxide per kg. of fat, with air bubbling through the samples at 98 C. A peroxide value of 20 was taken, according to normal practice, as corresponding to a commercially objectionable rancidity level.

In Table II, BHA represents a mixture of isomers consisting of 3-tertiarybutyl-4-hydroxyanisole and Z-tertiarybutyl-4-hydroxyanisole; BHT represents 3,5-ditertiarybutyl-4-hydroxy toluene. These antioxidants are frequently referred to in the art as butylated hydroxyanisole and butylated hydroxytoluene respectively. The latter compound is sometimes referred to as butylated p-cresol.

4 TABLE 11 AOM Stability in Hours Components of Antioxidant Composition tration, Weight Percent 30% Solute composed of:

66.7% BHA (20% of overall) 20.0% Propyl gallate (6% of overall) 13.3% Citric acid (4% of overall) 70% Solvent composed of: 100% Diacetin (70% of overall) 50% SolHu)te composed of: 100% BHA (50% of overa 50% Solvent composed of: 100% Triacetin (50% of overall) 30% Solmte composed of: 100% BHA (30% of overa 70% Solvent composed of- 100% Diacetin (70% of overall) 30% Solfite composed of: 100% BHT (30% of overa 70% Solvent composed of 100% Triacetin (70% of overall) 25% Solute composed of: 100% 2,4,5-Tri hydroxybutyrophenone (25% of overall) Solvent composed of: 100% Diacetin (75% of overall) 30% Solute composed of:

83.3% 2,4,5-Trihydroxybutyrophenone (25% of overall) 16.7% Citric acid (5% of overall). 70% Solvent composed of: 100% Dlacet of overall) Since most antioxidant compositions are mixtures of several components, it is impossible to assign specific limits to the concentration of acetins used. If the concentration of one component is varied, there will be an effect on the maximum concentration of the other components. However, as indicated in Table I, certain maximum concentrations are possible to achieve and, generally, the maximum concentration is the desirable one. Therefore, although rather specific solubilities may be determined for the acetins and one other material as shown by Table I, since the application of this invention to actual antioxidant compositions quite frequently deals with compositions having several components, no one of which is fixed except by the use for which the overall composition is intended, the invention is not to be limited by any specific expressed concentrations of acetins which can be used.

The antioxidant compositions with which this invention is concerned can be used to stabilize any of the various fatty materials subject to rancidity such as solid or liquid fats and oils, including the free fatty acids such as oleic acid, the animal fats such as lard and allow,

10% Solute composed of: 100% Hydroquinone (10% of overall) Solver}; composed of: Diacetin (90% of overal the vegetable oils such as soybean oil, corn oil, cottonseed oil, and peanut oil, the partial esters of any monoor diglycerides, and similar well-known fatty materials.

Thus, the acetins are useful and valuable as solvents,

tion for addition to fats and fatty oils, which composition consists essentially of a homogeneous solution of the following components by weight: (1) from 5 to 50% of a solute essentially composed of -10 parts of a synergist alone and in combination with themselves and other soland 5-42 parts of at least one compound normally effecvents, for fat and oil antioxidant compositions, particutive in stabilizing fats and fatty oils against oxidative larly those including diificultly fat soluble acid synergists, degradation and (2) from 95 to 50% of a solvent essenand provide a means whereby the antioxidant field is extially composed of -95 parts of at least one acetic acid panded toward more useful commercial antioxidant comester of glycerine and from 0-69 parts of at least one positions. l 10 organic compound effective as a solvent for the solute.

Although this invention has been illustrated to a con- Of course, those components (synergists and supples'ide'rable extent by Tables I and II, the data provided in mental solvents) where the parts can be 0 part by weight Table III, as presented hereinbelow, is illustrative of are optional components but if they are present there other examples of this invention. can be one or more of each of such optional components.

TABLE IIIa Antioxidant Compositions Giving Approximate Percentages by Weight (5:017) of (a Solute (b) Solvent and (0) Overall Weight I Components of Antioxidant Composition A B 0 D E F Solute components: I

Hydroqninnno H 015 1133.3 010 a33.3 e10 a30.0 e a3l.2 e10 9.75 e30 015 1133.3 010 a33.3 010 9.30.0 e15 9.31.2 e10 Propyl gallate. c6 a33.3 e10 a20.0 c6 a24.0 e12 a18.8 c6 2,4,s-Trihydroxybutyrnnh mn Y Citric acid a21.7 010 8.13.3 04 916.0 08 a18.8 06 9.25 010 Ascorbic acid...

Total solute alOO 046 e100 030 9.100 030 a100.0 e50 a100.0 (:32 3100 040 Solvent components:

rmnnnnfln gamm b33.3 e18 b14.3 010 014.3 010 1030 015 b1-1.7 clO b33.8 e20 riacet Glyoerylmonooleate b66.7 e36 b42.8 e b28.6 020 M0 020 b29.4 e20 b66.7 e Corn 0a-... M28 (:30 b57.1 e40 b30 e15 b55.9 e38 Propylene glycoL- Total solvent b100 4354 13100 070 M00 070 M00 050 M00 068 10100 060 TABLE IIIb Antioxidant Compositions Giving Approximate Percentages by Weight (i0. 1%) of (a) Solute, (b) Solvent and (0) Overall Weight Components of Antioxidant Composition G H I J K Solute components:

Hydroquinone. a100 c5 a33.3 c5 BHT 2175 030 a75 e30 BHA Propyl gallate 2,4,5-Trihydroxybutyrnn e (:5 9.33. 3 c5 Citric acid e25 010 9.25 010 a50 c5 Ascorbic acid. a33. 3 c5 Total solute 2.100 040 alOO 040 e100 e10 al00 c5 alOO e15 Solvent components:

, Mrmnm'ptin 1344.4 040 8.9.4 08

Diacetin bl6.7 010 1016.7 e10 b44.4 04o Triamfin blUO 095 9.9. 4 c8 Glyceryl monooleate.. b50.0 e30 b66.7 (:40 2.18.8 1316 Corn oil 1333.8 020 bl6.7 010 2162.4 053 Propylene glycol b11. 1 010 Total solvent 10100 060 b100 e b100 090 N00 e95 2.100 085 The antioxidant compositions shown in Table III were subjected to storage at l2 C. for more than 90 hours with no apparent adverse effects. Some of these compositions were rather viscous liquids at sub-zero temperatures but upon warming to room temperature, no separation was observed. Compositions F, G and H solidified at -l2 C. but upon warming to room temperature they were completely miscible. Antioxidant potencies for the compositions of Table III were analogous to those illustrated in Table II and depended upon the concentration of the solutes in the fat or oil serving as the substrate during the tests.

Analysis of the data presented in Tables I, II and III shows that advantageous embodiments of this invention are provided by a normally liquid antioxidant composi- The various numerical values for the parts by weight are based on the figures shown in the various tables and can be varied somewhat without departing from the scope of the invention.

The optional organic solvents which can be present are preferably one or more higher fatty acid glycerides (mono-, diand triglycerides) which are normally liquid. Such glycerides can be readily obtained from fats and fatty oils, e.g. animal or vegetable fats or oils. These glycerides are well known in the art as solvents for antioxidants. Quite obviously, those which are normally solids are not considered as useful solvents. The higher fatty acid glycerides can be obtained by reacting a fat or fatty oil with glycerine, usually in the presence of a catalyst.

Although the synergists are optional components, the use of acetins as solvents produces its most advantageous and unobvious results as to compositions containing synergists. As shown in Table III, from to parts of a synergist such as citric acid, phosphoric acid, ascorbic acid, or the like can be employed to achieve especially advantageous antioxidant compositions. The use of citric acid is normally of especially useful advantage.

Since, as already indicated, mixtures of antioxidants with higher fatty acid glycerides are well known in the art, care should be taken not to confuse the present invention with such disclosures as illustrated in U.S. Patent 2,745,749 where there is disclosed an acetylated monostearate described as a colorless, odorless and tasteless oil to which enough propyl gallate was added to prevent the oxidation of the oleoyl radical (present due to the fact that the mono-stearate used contained about 3% olein) when subjected to aeratio'n for more than 700 hours at 208 F. It is obvious that disclosures of this type involve the employment of very small percentages of antioxidant compounds in the total mixture. As those skilled in the art well know, the use of about 0.02% of an antioxidant is no'rmally adequate and percentages higher than 0.1 are rarely employed. In contrast, the antioxidant compositions of this invention contain at least 5% of a solute essentially composed of stabilizing compounds. According to most commercial applications of this invention, the percentage of solute would be at least 25% by weight of solute. Although the range from 5% to the probable commercial minimum of 25 is somewhat arbitrary, it is conceivable that some situations may exist where antioxidant compo'sitions of advantageous utility would contain solute within this range. In any event, the especially preferred embodiments of this invention containing solute in the range of from 25 to 50% are not even remotely conceivable as a result of any reasonable analysis of the prior art.

Since the acetins with which this invention is concerned are specific compounds and are vastly dilferent from the higher fatty acid glycerides, it should be noted that the acetins are by definition acetic acid esters of glycerine. The three acetins can also be called the monoacetate, the diacetate and the triacetate of glycerine. The term acetin is not generic to acetic acid esters of higher fatty acid monoand diglycerides. The term acetin as used in this specification is only generic to the three acetic acid esters of glycerine specifically encompassed within the term acetin.

Although the invention has been described in considerable detail with particular reference to certain preferred embodiments thereof, variations and modifications can be elfected within the spirit and scope of the invention as described hereinabove and as defined in the appended claims.

8 We claim: 1 1. A normally liquid antioxidant composition for addition to fats and fatty oils consisting essentially of from 5 to 50% by weight of active constituents composed of from 5 to 42 parts by weight of a phenolic antioxidant out of a total of 5 to 52 parts by weight of active constituents and from to 5% by weight of a solvent composed of from 10 to 95 parts by weight of an acetic acid ester of glycerine out of a total of 10 to 164 parts by weight of solvent.

2. An antioxidant composition as defined in claim 1 wherein the active constituents are present in an amount of from 25 to 50%.

3. An antioxidant composition as defined in claim 2 wherein the active constituents contain from 5 to 10 parts of a synergist selected from the group consisting of citric acid, phosphoric acid and ascorbic acid and from 5 to 42 parts of said phenolic antioxidant, and said solvent is essentially entirely composed of at least one member selected from the group consisting of an acetic acid ester of glycerine, propylene glycol and a normally liquid higher fatty acid glyceride from fats and fatty oils.

4. An antioxidant composition as defined in claim 3 wherein the synergist is citric acid.

5. An antioxidant composition as defined in claim 4 wherein the solvent is composed entirely of at least one acetic acid ester of glycerine.

6. An antioxidant composition as defined in claim '4 wherein said solvent contains from 35 to 69 parts of at least one of said normally liquid higher fatty acid glycerides obtained from fats and fatty oils.

7. An antioxidant composition as defined in claim 6 comprising tertiary butylhydroxyanisole, 3,5-ditertiarybutyl-4-hydroxytoluene, propyl gallate, citric acid, diacetin, and glyceryl mono-oleate.

8. An antioxidant composition as defined in claim 6 comprising tertiary butylhydroxyanisole, pro'pyl gallate, citric acid and diacetin. v

9. An antioxidant composition as defined in claim 6 comprising tertiary butylhydroxyanisole, propyl gallate, citric acid, diacetin and glyceryl mono-oleate.

10. An antioxidant composition as defined in claim 2 comprising tertiary butylhydroxyanisole and diacetin.

11. An antioxidant composition as defined in claim 2 comprising tertiary butylhydroxyanisole and triacetin.

References Cited in the file of this patent UNITED STATES PATENTS 2,073,256 Schmelkes et al. Mar. 9, 1937 2,408,904 Black Oct. 8, 1946 2,523,792 Vahlteich et al Sept. 23, 1950 2,645,581 Robison July 14, 1953 2,745,749 Feuge et al May 15, 1956 2,764,605 Embree et al. Sept. 25, 1956 

1. A NORMALLY LIQUID ANTIOXIDANT COMPOSITION FOR ADDITION TO FATS AND FATTY OILS CONSISTING ESSENTIALLY OF FROM 5 TO 50% BY WEIGHT OF ACTIVE CONSTITUENTS COMPOSED OF FROM 5 TO 42 PARTS BY WEIGHT OF A PHENOLIC ANTIOXIDANT OUT OF A TOTAL OF 5 TO 52 PARTS BY WEIGHT OF ACTIVE CONSTITUENTS AND FROM 95 TO 5% BY WEIGHT OF A SOLVENT COMPOSED OF FROM 10 TO 95 PARTS BY WEIGHT OF AN ACETIC ACID ESTER OF GLYCERINE OUT OF A TOTAL OF 10 TO 164 PARTS BY WEIGHT OF SOLVENT. 